They are usually considered good companions. I am surprised that in Zone 4b you finish the peas in June. Here their main season is July 1-July10. So in my opinion their seasons will overlap some. In fact, in Michigan I get romano beans at the same time or slightly earlier than peas.

Either way, another double use for them is to put collard or cabbage on the shady side, and chard on the sunny side. The greens will not help the beans, but the beans will help the greens a lot. Cabbage will appreciate the summer shade and finish nicely in the Fall.